Various processes have been developed to repair or prevent the occurrence of scratches, nicks, cracks, or other similar flaws on surfaces of glass articles, e.g., glass containers, bottles, jars, and the like. In the glass container industry, one or more protective coatings are conventionally applied to the exterior surfaces of the glass containers during the manufacturing process to prevent or reduce the occurrence of flaws on the surfaces of the containers. More specifically, in a conventional glass container manufacturing process, the glass containers are typically coated with metal oxides, e.g., oxides of tin, titanium, vanadium, or zirconium at a “hot end” of the process with respect to an annealing lehr, and are coated again with an organic coating material at a “cold end” of the process with respect to the annealing lehr. U.S. patents that illustrate coating processes of this type include: U.S. Pat. Nos. 3,323,889; 3,407,085; 3,414,429; 3,418,154; 3,425,859; 3,445,269; 3,498,825; 3,554,787; and 3,598,632.
A general object of the present disclosure, in accordance with one aspect of the disclosure, is to provide a glass container having a microwave susceptor coating formed on an exterior surface thereof, and a surface treatment process for the coated glass container that can be used to fill-in or “heal” flaws on the exterior surface of the glass container.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
A process for healing one or more surface flaws in an exterior portion of a glass container that includes in accordance with one aspect of the disclosure includes: (a) forming a microwave susceptor coating on an exterior surface of the glass container, (b) exposing the glass container to microwave radiation to selectively and locally heat and melt one or more regions of glass in the exterior portion of the glass container, and (c) terminating said step (b) such that the one or more regions of glass in the exterior portion of the glass container are quenched and cooled by glass beneath the one or more regions.
In accordance with another aspect of the disclosure, there is provided a process for manufacturing a glass container that includes: (a) forming a glass substrate that defines the shape of the glass container, (b) forming a microwave susceptor coating on an exterior surface of the glass substrate, (c) exposing the glass container to microwave radiation to selectively and locally heat and melt at least one region of glass in an exterior portion of the glass substrate to a temperature above 500 degrees Celsius, while also maintaining a remaining portion of the glass substrate at a temperature below 500 degrees Celsius, (d) annealing the glass container, and (e) forming a cold end coating over the microwave susceptor coating on the exterior surface of the glass substrate.
In accordance with yet another aspect of the disclosure, there is provided a glass container that includes: a glass substrate and a microwave susceptor coating formed on the exterior surface of the glass substrate. The glass substrate defines the shape of the glass container and provides the container with a closed base at an axial end of the container, a body extending axially from the base and being circumferentially closed, and an open mouth at another axial end of the glass container opposite the base. The glass substrate has one or more surface flaws that extend from the exterior surface of the substrate, into an exterior portion of the substrate. The microwave susceptor coating is formed on the exterior surface of the glass substrate such that one or more local regions of the coating extend from the exterior surface of the substrate and into the exterior portion of the substrate.